U.S. patent application number 15/218194 was filed with the patent office on 2017-08-24 for blower duct, blower device, and image forming apparatus.
This patent application is currently assigned to FUJI XEROX CO., LTD.. The applicant listed for this patent is FUJI XEROX CO., LTD.. Invention is credited to Masafumi KUDO, Yasunori MOMOMURA, Yuki NAGAMORI.
Application Number | 20170242362 15/218194 |
Document ID | / |
Family ID | 59629967 |
Filed Date | 2017-08-24 |
United States Patent
Application |
20170242362 |
Kind Code |
A1 |
MOMOMURA; Yasunori ; et
al. |
August 24, 2017 |
BLOWER DUCT, BLOWER DEVICE, AND IMAGE FORMING APPARATUS
Abstract
A blower duct includes a path section and multiple suppressing
sections. The path section connects an inlet and an outlet and
allows air to flow therethrough. The suppressing sections are
provided at different locations in the air flowing direction and
suppress the flow of the air. The path section at least has an
entrance path section and a first bent path section. One of the
suppressing sections is a first suppressing section including a
blocking portion and openings. The blocking portion is disposed in
the first bent path section and blocks the flow of the air. The
openings are disposed at different positions in one direction and
include a first opening disposed closest to the inlet at a first
height position where a height from a reference base surface of the
first bent path section is larger than the remaining opening or
openings.
Inventors: |
MOMOMURA; Yasunori;
(Kanagawa, JP) ; NAGAMORI; Yuki; (Kanagawa,
JP) ; KUDO; Masafumi; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI XEROX CO., LTD. |
Tokyo |
|
JP |
|
|
Assignee: |
FUJI XEROX CO., LTD.
Tokyo
JP
|
Family ID: |
59629967 |
Appl. No.: |
15/218194 |
Filed: |
July 25, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G 15/0291 20130101;
G03G 15/0258 20130101; G03G 21/206 20130101 |
International
Class: |
G03G 15/02 20060101
G03G015/02; G03G 21/20 20060101 G03G021/20 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 18, 2016 |
JP |
2016-029031 |
Claims
1. A blower duct comprising: a path section having a path that
connects an inlet and an outlet and allows air to flow through the
path, the inlet taking in the air, the outlet ejecting the air
taken in from the inlet and having an opening shape that is long in
one direction; and a plurality of suppressing sections that are
provided at different locations in a direction in which the air
flows through the path of the path section and that suppress flow
of the air, wherein the path section at least has an entrance path
section and a first bent path section, the entrance path section
having a path whose one end is provided with the inlet, the first
bent path section being bent from an intermediate position of the
entrance path section and having a path with a cross-sectional
shape that is long in one direction, wherein one of the suppressing
sections is a first suppressing section including a blocking
portion and a plurality of openings, the blocking portion being
disposed in a part of the path of the first bent path section and
extending in the one direction of the cross-sectional shape so as
to block the flow of the air, the plurality of openings each having
an opening shape that is long in the one direction of the
cross-sectional shape and being disposed at different positions in
the one direction of the cross-sectional shape, and wherein the
openings include a first opening that is disposed closest to the
inlet in the one direction of the cross-sectional shape, the first
opening being disposed at a first height position, which is where a
height from a reference base surface of the path of the first bent
path section is larger than the remaining one or more openings.
2. The blower duct according to claim 1, wherein the openings
include a second opening that is disposed farthest from the inlet
in a longitudinal direction of the cross-sectional shape, the
second opening being disposed at a second height position, which is
where the height from the base surface is second largest.
3. The blower duct according to claim 2, wherein the openings
include a remaining opening disposed at least between the first
opening and the second opening, the remaining opening being
disposed at a third height position that is lower than the second
height position.
4. The blower duct according to claim 3, wherein the remaining
opening includes a plurality of remaining openings, and wherein the
remaining openings are disposed at respective height positions such
that the remaining opening disposed closer toward the inlet in the
longitudinal direction of the cross-sectional shape decreases in
height from the base surface in a stepwise manner within the third
height position.
5. The blower duct according to claim 1, wherein the plurality of
openings are disposed to have a positional relationship such that
ends of adjoining openings are located at aligned positions or
partially overlapping positions in a longitudinal direction of the
cross-sectional shape.
6. A blower device comprising: a blower that sends air; and the
blower duct according to claim 1 that takes in the air sent from
the blower.
7. An image forming apparatus comprising: an image forming unit
that forms an image; and the blower device according to claim 6
that blows air onto a corona discharger that is long in one
direction.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based on and claims priority under 35
USC 119 from Japanese Patent Application No. 2016-029031 filed Feb.
18, 2016.
BACKGROUND
Technical Field
[0002] The present invention relates to blower ducts, blower
devices, and image forming apparatuses.
SUMMARY
[0003] According to an aspect of the invention, there is provided a
blower duct including a path section and multiple suppressing
sections. The path section has a path that connects an inlet and an
outlet and allows air to flow through the path. The inlet takes in
the air, and the outlet ejects the air taken in from the inlet and
has an opening shape that is long in one direction. The multiple
suppressing sections are provided at different locations in a
direction in which the air flows through the path of the path
section and suppress the flow of the air. The path section at least
has an entrance path section and a first bent path section. The
entrance path section has a path whose one end is provided with the
inlet. The first bent path section is bent from an intermediate
position of the entrance path section and has a path with a
cross-sectional shape that is long in one direction. One of the
suppressing sections is a first suppressing section including a
blocking portion and multiple openings. The blocking portion is
disposed in a part of the path of the first bent path section and
extends in the one direction of the cross-sectional shape so as to
block the flow of the air. The multiple openings each have an
opening shape that is long in the one direction of the
cross-sectional shape and are disposed at different positions in
the one direction of the cross-sectional shape. The openings
include a first opening that is disposed closest to the inlet in
the one direction of the cross-sectional shape. The first opening
is disposed at a first height position, which is where a height
from a reference base surface of the path of the first bent path
section is larger than the remaining one or more openings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Exemplary embodiments of the present invention will be
described in detail based on the following figures, wherein:
[0005] FIG. 1 schematically illustrates an image forming apparatus
equipped with a blower device according to a first exemplary
embodiment;
[0006] FIG. 2 is a perspective view schematically illustrating a
charging device constituted of a corona discharger provided in the
image forming apparatus in FIG. 1;
[0007] FIG. 3 is a perspective view schematically illustrating the
blower device applied to the charging device in FIG. 2;
[0008] FIG. 4 is a cross-sectional view of the blower device
(blower duct) in FIG. 3, taken along line IV-IV;
[0009] FIG. 5 schematically illustrates the blower device in FIG.
3, as viewed from above;
[0010] FIG. 6 schematically illustrates the blower device in FIG.
3, as viewed from below (i.e., from an outlet);
[0011] FIG. 7 is an enlarged view of a first suppressing section in
the blower device (blower duct) in FIG. 3;
[0012] FIG. 8 is an enlarged view illustrating a detailed
configuration of the first suppressing section in FIG. 7;
[0013] FIG. 9 illustrates the operational state of the blower
device in FIG. 3;
[0014] FIG. 10 is a graph illustrating a result of a first test
related to the characteristics of the blower duct according to the
exemplary embodiment;
[0015] FIG. 11 is a graph illustrating a result of a second test
related to the characteristics of the blower duct according to the
exemplary embodiment;
[0016] FIGS. 12A to 12C illustrate a result of a third test related
to the characteristics of the blower duct according to the
exemplary embodiment;
[0017] FIG. 13 is an enlarged view illustrating another
configuration example of the first suppressing section;
[0018] FIG. 14 is an enlarged view illustrating another
configuration example of the first suppressing section;
[0019] FIG. 15 schematically illustrates another configuration
example of the blower duct, as viewed from above (or from a lateral
direction);
[0020] FIG. 16 is a cross-sectional view of the blower duct in FIG.
15, taken along line XVI-XVI;
[0021] FIG. 17 is a cross-sectional view schematically illustrating
a blower duct of a comparative example;
[0022] FIG. 18 is an enlarged view of a first suppressing section
in the blower duct of the comparative example;
[0023] FIG. 19 is a graph illustrating a result of the first test
related to the characteristics of the blower duct of the
comparative example; and
[0024] FIGS. 20A to 20C illustrate a result of the third test
related to the characteristics of the blower duct of the
comparative example.
DETAILED DESCRIPTION
[0025] Exemplary embodiments of the present invention will be
described below with reference to the appended drawings.
First Exemplary Embodiment
[0026] FIGS. 1 to 4 illustrate a blower duct according to a first
exemplary embodiment, a blower device equipped with the blower
duct, and an image forming apparatus equipped with the blower duct.
Specifically, FIG. 1 schematically illustrates the image forming
apparatus, FIG. 2 illustrates a charging device as an example of a
corona discharger to which air is blown by the blower duct or the
blower device, FIG. 3 schematically illustrates the blower duct or
the blower device, and FIG. 4 is a cross-sectional view of, for
example, the blower duct.
[0027] Configuration of Image Forming Apparatus
[0028] As shown in FIG. 1, an image forming apparatus 1 has a
housing 10 constituted of, for example, a support frame and an
outer cover. For example, the housing 10 has disposed therein an
image forming unit 20 that forms a toner image formed of a toner as
a developer and transfers the toner image onto recording paper 9 as
an example of a recording medium, a paper feeding device 30 that
accommodates and transports the recording paper 9 to be fed to the
image forming unit 20, and a fixing device 35 that fixes the toner
image formed by the image forming unit 20 onto the recording paper
9.
[0029] For example, the image forming unit 20 is of a known
electrophotographic type. The image forming unit 20 according to
the first exemplary embodiment includes a photoconductor drum 21
that is rotationally driven in a direction indicated by an arrow A;
a charging device 4 that electrostatically charges, to a
predetermined potential, a peripheral surface serving as an image
formation region of the photoconductor drum 21; an exposure device
23 that radiates light (indicated by a dotted line with an arrow)
based on image information (signal) input from the outside onto the
electrostatically-charged peripheral surface of the photoconductor
drum 21 so as to form an electrostatic latent image thereon; a
developing device 24 that develops the electrostatic latent image
into a toner image by using the toner; a transfer device 25 that
transfers the toner image from the photoconductor drum 21 to the
recording paper 9; and a cleaning device 26 that cleans the
peripheral surface of the photoconductor drum 21 after the transfer
process by removing waste, such as residual toner, therefrom.
[0030] A corona discharger is used as the charging device 4. As
shown in, for example, FIG. 2, the charging device 4 constituted of
the corona discharger is a so-called scorotron-type corona
discharger.
[0031] Specifically, the charging device 4 includes a shield case
40 as an example of an enclosure member, two end supporters (not
shown), two corona discharge wires 41A and 41B, and a porous grid
electrode (electric-field adjustment plate) 42. The shield case 40
has a rectangular top plate 40a and side plates 40b and 40c hanging
downward from the long edges, which extend in a longitudinal
direction B, of the top plate 40a. The two end supporters are
respectively attached to the opposite ends (i.e., short edges) of
the shield case 40 in the longitudinal direction B. The two corona
discharge wires 41A and 41B are disposed within a long internal
space formed between the two end supporters and extending in the
longitudinal direction B of the shield case 40. The two corona
discharge wires 41A and 41B are attached in a manner such that they
extend substantially parallel to each other. The grid electrode 42
is attached to a discharge opening in the lower surface of the
shield case 40 so as to substantially cover the discharge opening
and to be located between the corona discharge wires 41A and 41B
and the peripheral surface of the photoconductor drum 21. Reference
character 40d in, for example, FIG. 4 denotes a partition that
partitions, in the longitudinal direction B of the shield case 40,
the space in which the two corona discharge wires 41A and 41B are
disposed. The discharge opening has a rectangular opening
shape.
[0032] In the charging device 4, the two corona discharge wires 41A
and 41B are disposed so as to face the peripheral surface of the
photoconductor drum 21 with a predetermined distance (e.g., a
discharge gap) therebetween and also to face the image formation
region of the photoconductor drum 21 along a rotation shaft
thereof. Furthermore, in the charging device 4, when image forming
operation is to be performed, a charge voltage is supplied from a
power source (not shown) between each of the corona discharge wires
41A and 41B and the photoconductor drum 21.
[0033] Moreover, as the charging device 4 is used, the corona
discharge wires 41A and 41B and the grid electrode 42 may become
contaminated due to paper particles from the recording paper 9,
discharge products produced from corona discharge, and substances
(waste), such as external additives in the toner. This may result
in charge defects, such as uneven charge, due to insufficient or
nonuniform corona discharge. Thus, for the prevention or reduction
of the adhesion of waste onto the corona discharge wires 41A and
41B and the grid electrode 42, a blower device 5 for blowing air
toward the corona discharge wires 41A and 41B and the grid
electrode 42 is provided for the charging device 4. The top plate
40a of the shield case 40 of the charging device 4 has an air inlet
opening 43 for taking in the air blown from the blower device 5.
The air inlet opening 43 has a rectangular opening shape extending
in the longitudinal direction B of the shield case 40. Furthermore,
as shown in, for example, FIG. 9, the shield case 40 has gaps S3
and S4 respectively at the lower edge of the side plate 40b located
at the upstream side in a rotational direction A of the
photoconductor drum 21 and at the lower edge of the side plate 40c
located at the downstream side. The gaps S3 and S4 are spaced apart
from the peripheral surface of the photoconductor drum 21 by the
same distance (discharge gap).
[0034] A detailed description of the blower device 5 will be
provided later.
[0035] The paper feeding device 30 includes a paper accommodation
body 31 that accommodates a stack of multiple sheets of recording
paper 9 of, for example, a predetermined size and type to be used
for image formation, and a delivering device 32 that delivers the
sheets of recording paper 9 accommodated in the paper accommodation
body 31 one-by-one toward a transport path. When it is time to feed
the recording paper 9, the sheets of recording paper 9 are
delivered one-by-one. In accordance with the intended use, multiple
paper accommodation bodies 31 are provided. A two-dot chain line
with an arrow in FIG. 1 denotes a transport path along which the
recording paper 9 is transported and moved inside the housing 10.
The transport path for the recording paper 9 is constituted of, for
example, multiple pairs of paper transport rollers 33a and 33b and
a transport guide member (not shown).
[0036] The fixing device 35 includes a heating rotation body 37 and
a pressing rotation body 38 inside a housing 36 having an entrance
port and an exit port through which the recording paper 9 passes.
The heating rotation body 37 is of, for example, a roller type or a
belt type whose surface temperature is heated to and maintained at
a predetermined temperature by a heater. The pressing rotation body
38 is of, for example, a roller type or a belt type that is
rotationally driven by coming into contact with the heating
rotation body 37, with a predetermined pressure, substantially
along a shaft thereof. In the fixing device 35, a contact section
formed as a result of the heating rotation body 37 and the pressing
rotation body 38 coming into contact with each other serves as a
fixing processor where a predetermined fixing process (heating and
pressing) is performed. The fixing process is performed by causing
the recording paper 9 that has undergone a toner-image transport
process to enter and pass through the contact section.
[0037] Image forming operation is performed by the image forming
apparatus 1 in the following manner. Basic image forming operation
performed when forming an image onto one face of the recording
paper 9 will be described here as a representative example.
[0038] In the image forming apparatus 1, for example, when a
controller (not shown) receives an image-forming-operation start
command, the peripheral surface of the photoconductor drum 21 that
starts to rotate in the image forming unit 20 is electrostatically
charged to a predetermined polarity and potential by the charging
device 4. In the charging device 4, a charge voltage is applied to
each of the two corona discharge wires 41A and 41B so that corona
discharge is generated in a state where an electric field is
generated between each corona discharge wire 41A, 41B and the
peripheral surface of the photoconductor drum 21, whereby the
peripheral surface of the photoconductor drum 21 is
electrostatically charged to a predetermined potential. In this
case, the charge potential of the photoconductor drum 21 is
adjusted by the grid electrode 42.
[0039] Subsequently, the exposure device 23 radiates light based on
image information onto the electrostatically-charged peripheral
surface of the photoconductor drum 21 so as to form an
electrostatic latent image having a predetermined potential. Then,
as the electrostatic latent image formed on the photoconductor drum
21 passes through the developing device 24, the electrostatic
latent image is developed into a visible toner image by using a
toner electrostatically charged to a predetermined polarity and
supplied from a developing roller.
[0040] Subsequently, when the toner image formed on the
photoconductor drum 21 is transported to a transfer position facing
the transfer device 25 due to the rotation of the photoconductor
drum 21, a transfer function of the transfer device 25 causes the
toner image to be transferred onto the recording paper 9, which is
fed from the paper feeding device 30 via the transport path in
accordance with this timing. After this transfer process, the
peripheral surface of the photoconductor drum 21 is cleaned by the
cleaning device 26.
[0041] Then, the recording paper 9 having the toner image
transferred thereon at the image forming unit 20 is separated from
the photoconductor drum 21 and is subsequently transported to the
fixing device 35. As the recording paper 9 passes through the
contact section between the heating rotation body 37 and the
pressing rotation body 38 of the fixing device 35, the recording
paper 9 is pressed and heated so that the toner image fuses and
becomes fixed onto the recording paper 9. Upon completion of this
fixing process, the recording paper 9 is output from the fixing
device 35 and is transported and accommodated into an output-paper
accommodation section (not shown) provided, for example, outside
the housing 10.
[0042] Accordingly, a monochromatic image formed of one color of
toner is formed on one face of a single sheet of recording paper 9,
and the basic image forming operation ends. If there is a command
for forming images onto multiple sheets of recording paper 9, the
above-described series of processes is similarly repeated for the
number of sheets.
[0043] Configuration of Blower Device
[0044] Next, the blower device 5 will be described.
[0045] As shown in, for example, FIGS. 1 and 3, the blower device 5
includes a blower 50 having a rotating fan that blows air and a
blower duct 51A that takes in the air blown from the blower 50 and
guides and ejects the air to the charging device 4 as an example of
a target structure to which the air is blown.
[0046] For example, a radial-flow blower fan is used as the blower
50. The blower 50 is driven and controlled so as to blow a
predetermined amount of air.
[0047] As shown in, for example, FIGS. 3 to 7, the blower duct 51A
has a path section (body section) 54 and two suppressing sections
(i.e., a first suppressing section 61 and a second suppressing
section 62). In the path section 54, a path TS that connects an
inlet 52, which takes in the air blown from the blower 50, and an
outlet 53, which ejects the air taken in through the inlet 52, for
allowing the air to flow therethrough is bent twice at intermediate
positions of the path section 54. The two suppressing sections
suppress the flow of air and are provided at different locations in
the direction in which the air flows through the path TS of the
path section 54. The outlet 53 is disposed facing a
longitudinal-direction-B portion (i.e., the air inlet opening 43 in
the top plate 40a of the shield case 40) that is long in one
direction of the charging device 4 to which the air taken in
through the inlet 52 is blown.
[0048] The inlet 52 of the blower duct 51A has a rectangular
opening shape in its entirety, which is slightly longer in the
vertical direction, or has a square opening shape. A connection
duct 55 for connecting the inlet 52 and the blower 50 so as to
deliver the air produced by the blower 50 to the inlet 52 is
attached to the inlet 52 of the blower duct 51A (FIG. 3).
[0049] The outlet 53 of the blower duct 51A has, for example, a
rectangular opening shape that is long in one direction.
Furthermore, the outlet 53 has a different opening shape (but
including a similar opening shape) from that of the inlet 52. The
outlet 53 in the first exemplary embodiment is formed in a
rectangular opening shape such that the entire opening thereof
substantially completely faces the air inlet opening 43 serving as
a portion, which is long in one direction, of the shield case 40 of
the charging device 4 to which air is blown. Furthermore, as shown
in, for example, FIGS. 4 and 6, the outlet 53 is formed so as to
have a slightly narrower opening area than the entire terminal end
of a section located at the outlet 53 side of the path section 54
(i.e., a path TS of a second bent path section 54C).
[0050] As shown in, for example, FIGS. 3 to 5, the path section 54
of the blower duct 51A is constituted of an entrance path section
54A, a first bent path section 54B, and a second bent path section
54C.
[0051] With regard to the entrance path section 54A, a first open
end thereof serves as the inlet 52, and a second end thereof is
closed. The entire entrance path section 54A is a path section with
an angular tubular shape having a path TS1 extending linearly and
substantially parallel to the longitudinal direction B of the
outlet 53 (i.e., the same as the longitudinal direction B of the
charging device 4).
[0052] The first bent path section 54B is a bent path section with
an angular tubular shape having a path TS2 that is bent at a
substantially right angle in the substantially horizontal direction
(i.e., a direction substantially parallel to a direction indicated
by a coordinate axis X), which is a lateral direction, from an area
(intermediate area) located toward the second end of the entrance
path section 54A. Moreover, as compared with the entrance path
section 54A, the first bent path section 54B has, for example, a
rectangular cross-sectional shape that is long in one direction and
whose width W (i.e., the dimension in the longitudinal direction B)
is increased while the height H of the path TS2 is maintained equal
to the height H of the path TS1 of the entrance path section 54A.
With regard to the first bent path section 54B in the first
exemplary embodiment, a longitudinal direction D, which is the
aforementioned one direction of the rectangular cross-sectional
shape, in the path TS1 after the bent area is set to be
substantially parallel to the longitudinal direction B of the
outlet 53.
[0053] The second bent path section 54C has a path TS3 that is bent
in a downward direction (i.e., a direction substantially parallel
to a direction indicated by a coordinate axis Y), which is a
predetermined direction, from a downstream end (terminal end) of
the first bent path section 54B in the direction in which the air
flows through the path TS2. Moreover, as compared with the first
bent path section 54B, the second bent path section 54C has a
rectangular shape that is wider in the lateral direction and is
bent downward while the width (i.e., the dimension in the
longitudinal direction B) of the path TS3 is maintained equal to
the width W of the path TS2 of the first bent path section 54B.
Furthermore, the second bent path section 54C is formed to have
dimensions such that the bent terminal end thereof is connectable
close to an area of the charging device 4 to which air is to be
blown (i.e., the air inlet opening 43 of the shield case 40 in the
first exemplary embodiment). The terminal end of the path TS3 in
the second bent path section 54C is provided with the outlet 53
having the configuration described above.
[0054] As shown in, for example, FIGS. 3 to 5, and 7, the first
suppressing section 61 in the blower duct 51A includes a blocking
portion 65 and multiple openings 66 (66A to 66C). The blocking
portion 65 is located in a part of the path TS2 of the first bent
path section 54B and extends in the longitudinal direction D of the
cross-sectional shape of the path TS2 so as to block the flow of
air. The openings 66 each have a rectangular opening shape that is
long in the longitudinal direction D of the cross-sectional shape
of the path TS2 and are arranged at different positions in the
longitudinal direction D of the cross-sectional shape.
[0055] The blocking portion 65 in the first suppressing section 61
is provided as a plate-shaped member in the bent area after the
path TS2 of the first bent path section 54B and is disposed so as
to traverse the path TS2 in the longitudinal direction D of the
cross-sectional shape of the path TS2. Furthermore, the blocking
portion 65 in the first exemplary embodiment is disposed such that
an inner wall surface 65a, which is located at the upstream side in
the air flowing direction, is displaced by a predetermined distance
N from an end 52a, which is located closer toward the outlet 53
relative to the inlet 52, toward the downstream side in the air
flowing direction in the first bent path section 54B (FIG. 4).
Moreover, the upstream inner wall surface 65a and a downstream
inner wall surface 65b of the blocking portion 65 are both flat
surfaces. The thickness (M) of the blocking portion 65 in the air
flowing direction is set to a dimension corresponding to a
through-width of each opening 66, which will be described
below.
[0056] For example, as shown in FIGS. 4, 7, and 8, the multiple
openings 66 in the first suppressing section 61 include a total of
three openings, namely, a first opening 66A, a second opening 66B,
and a third opening 66C.
[0057] As described above, the three openings 66A to 66C all have a
rectangular opening shape and are provided in predetermined areas
of the blocking portion 65 in actuality. With regard to the
rectangular opening shape of each of the openings 66A to 66C, the
openings 66A to 66C have predetermined lengths La, Lb, and Lc
(i.e., the lengths of the long sides) in the longitudinal direction
D of the cross-sectional shape of the path TS2 and predetermined
heights Ka, Kb, and Kc (i.e., the lengths of the short sides). In
this case, the lengths La, Lb, and Lc are set to identical
dimensions but may alternatively set to partially or entirely
different dimensions. Likewise, the heights Ka, Kb, and Kc are set
to identical dimensions but may alternatively set to partially or
entirely different dimensions. Furthermore, with regard to each of
the openings 66A to 66C, the path length M, which is the length in
the air passing direction as shown in FIG. 4, is set to a
predetermined dimension. This path length M also corresponds to the
thickness of the plate-shaped member constituting the blocking
portion 65, as described above.
[0058] As shown in, for example, FIGS. 7 and 8, the first opening
66A is an opening disposed at the closest position to the inlet 52
in the longitudinal direction D of the cross-sectional shape of the
path TS2 in the first bent path section 54B and is disposed at a
first height position h1, which is where the height H from a
reference base surface 54d of the path TS2 of the first bent path
section 54B is relatively the largest. The second opening 66B is an
opening disposed at the farthest position from the inlet 52 in the
longitudinal direction D of the cross-sectional shape of the path
TS2 and is disposed at a second height position h2 (<h1), which
is where the height H from the base surface 54d is the second
largest. The third opening 66C is the remaining opening disposed at
least between the first opening 66A and the second opening 66B and
is disposed at a third height position h3 (<h2), which is lower
than the second height position h2.
[0059] The aforementioned reference base surface 54d is a surface
selected for the sake of convenience as a reference location for
specifying the positions of the multiple openings 66 in the height
direction. Of the two long sides of the rectangular cross-sectional
shape of the path TS2 in the first bent path section 54B, a surface
including the long side located closer to the outlet 53 is selected
as a reference base surface (54d) in the first exemplary
embodiment. The reference base surface 54d in the first exemplary
embodiment is formed as a flat surface that extends continuously
from a base surface 54e of the path TS1 in the entrance path
section 54A. Furthermore, the height positions h1 to h3 are set
with reference to central positions of the heights Ka, Kb, and Kc
of the openings 66A to 66C, respectively.
[0060] Furthermore, as shown in, for example, FIGS. 7 and 8, the
three openings 66A to 66C have positional relationships such that
the ends of adjoining openings 66 partially overlap each other in
the longitudinal direction D of the cross-sectional shape of the
path TS2.
[0061] In detail, the first opening 66A and the third opening 66C,
which adjoin each other, have a positional relationship such that a
first end 66Aa of the first opening 66A and a first end 66Ca of the
third opening 66C overlap each other by a predetermined overlapping
amount J1. Moreover, the second opening 66B and the third opening
66C, which adjoin each other, have a positional relationship such
that a first end 66Ba of the second opening 66B and a second end
66Cb of the third opening 66C overlap each other by a predetermined
overlapping amount J2. In this case, the two overlapping amounts J1
and J2 are set equal to each other but may alternatively be set to
different dimensions.
[0062] Furthermore, as shown in, for example, FIGS. 7 and 8, the
three openings 66A to 66C are disposed such that the ends thereof
adjacent to four inner wall surfaces constituting the path TS2 of
the first bent path section 54B are slightly disposed away from the
adjacent inner wall surfaces. Alternatively, the three openings 66A
to 66C may be disposed such that the ends thereof adjacent to the
four inner wall surfaces are partially or entirely in contact with
the adjacent inner wall surfaces.
[0063] For example, the first suppressing section 61 may be a
member configured by providing (cutting out) through-holes serving
as the three openings 66A to 66C in a plate-shaped member (with a
thickness M) having the same shape as the cross-sectional shape of
the path TS2 of the first bent path section 54B. In this case, in
the plate-shaped member, a remaining portion excluding the three
openings 66A to 66C serves as the blocking portion 65. The blocking
portion 65 including the openings 66 in the first suppressing
section 61 may be obtained by integral molding using the same
material as the blower duct 51A or may be attached to the blower
duct 51A after being formed using a material different
therefrom.
[0064] The position (i.e., the aforementioned distance N) of the
blocking portion 65 in the first suppressing section 61, the
lengths La, Lb, and Lc and the heights Ka, Kb, and Kc of the
opening shapes of the openings 66A to 66C, and the path length M
thereof (which also corresponds to the thickness of the blocking
portion 65) are selected and set in view of making the flow speed
of air flowing into the first bent path section 54B from the
entrance path section 54A uniform as much as possible. Furthermore,
these values are also set in view of, for example, the dimensions
(capacities) of the paths TS in the blower duct 51A and the flow
rate per unit time of air to be blown to the blower duct 51A or the
charging device 4.
[0065] As shown in, for example, FIGS. 4 and 6, the second
suppressing section 62 in the blower duct 51A is provided as a
suppressing section that blocks the outlet 53 by using an air
permeable member 70 having multiple air permeable sections 71.
[0066] The multiple air permeable sections 71 are
linearly-extending through-holes each having a substantially
circular opening shape. For example, the multiple air permeable
sections 71 are arranged at regular pitch in the longitudinal
direction B of the opening shape of the outlet 53 and are also
arranged at pitch equal to the regular pitch in a lateral direction
C orthogonal to the longitudinal direction B so as to form multiple
rows (e.g., seven rows). Specifically, the multiple air permeable
sections (holes) 71 are substantially uniformly arranged in the
entire region of the outlet 53. Accordingly, the air permeable
member 70 having the multiple air permeable sections 71 arranged
therein is a porous plate having the multiple air permeable
sections (holes) 71 arranged in a plate-shaped member.
[0067] For example, the air permeable member 70 constituting the
second suppressing section 62 may be obtained by integral molding
using the same material as the blower duct 51A or may be attached
to the blower duct 51A after being formed using a material
different therefrom. The opening shape, the opening dimensions, the
hole length, and the hole density of the air permeable sections
(holes) 71 are selected and set in view of making the flow speed of
air flowing out from the second bent path section 54C via the
outlet 53 uniform as much as possible, and are also set in view of
the dimensions (capacities) of the paths TS in the blower duct 51A
and the flow rate per unit time of air to be blown to the blower
duct 51A or the charging device 4.
[0068] Operation of Blower Device
[0069] The operation of the blower device 5 (i.e., operation
arising from the blower duct 51A) will be described below.
[0070] In the blower device 5, when a drive setting timing is
reached, such as at the time of image forming operation, the blower
50 is first rotationally driven so as to deliver a predetermined
amount of air. The air (E) delivered from the activated blower 50
is taken in through the inlet 52 of the blower duct 51A via the
connection duct 55, and flows first into the path TS1 of the
entrance path section 54A (FIG. 5).
[0071] Subsequently, as shown in FIGS. 5 and 9, the air (E) taken
into the blower duct 51A travels through the path TS1 of the
entrance path section 54A. While traveling through the path TS1 or
after turning around by hitting against the closed end of the path
TS1, the air (E) curves so that the traveling direction thereof
changes, whereby the air (E) is caused to flow into the path TS2 of
the first bent path section 54B. A portion of the air (E1)
delivered to the path TS2 of the first bent path section 54B is
blocked by the blocking portion 65 of the first suppressing section
61, whereas the remaining portion (e.g., see arrows E1a, E1b, and
E1c in FIG. 5) travels and passes through the three openings 66A to
66C in the first suppressing section 61.
[0072] In this case, the air (E1) reaching the first suppressing
section 61 is distributed to the three openings 66A to 66C disposed
at different positions in the longitudinal direction D of the
cross-sectional shape of the path TS2 in the first bent path
section 54B and located at predetermined height positions h1, h2,
and h3 with different heights H from the reference base surface 54d
of the path TS2. Furthermore, when passing through the three
openings 66A to 66C, the air (E1a, E1b, and E1c) increases in
pressure by passing through the three openings 66A to 66C that have
relatively narrower opening areas than the cross-sectional area of
the cross-sectional shape of the path TS2 in the first bent path
section 54B. Ultimately, the air (E1a, E1b, and E1c) flows out from
the openings 66A to 66C.
[0073] Subsequently, the air (E2a, E2b, and E2c) passing through
the three openings 66A to 66C and flowing into the path TS3 of the
second bent path section 54C travels linearly through the path TS3
or temporarily moves in a circulating manner therein and
subsequently travels toward the outlet 53 located at the terminal
end (i.e., the lower end) of the path TS3 of the second bent path
section 54C bent downward from the first bent path section 54B.
[0074] In this case, the air (E2a, E2b, and E2c) passing through
the three openings 66A to 66C and flowing into the path TS3 of the
second bent path section 54C flows through different positions in
the path TS3 (and also in the remaining portion of the path TS2 to
be precise) from the three openings 66A to 66C disposed at
different positions, as described above. Moreover, in this case,
the air (E2a, E2b, and E2c) flowing into the path TS3 of the second
bent path section 54C flows into the downstream path TS3 having a
capacity larger than those of the three openings 66A to 66C in the
first suppressing section 61 so as to travel distributively through
the path TS3 and to partially turn therein. Thus, a portion of the
air is temporarily retained within the path TS3 in a circulating
manner, so that unevenness in flow speed may be reduced.
[0075] Finally, a portion of the air (E2a, E2b, and E2c) flowing
into the path TS3 of the second bent path section 54C passes
through the multiple air permeable sections (holes) 71 in the air
permeable member 70 of the second suppressing section 62 provided
at the outlet 53, as indicated by arrows E3 in FIG. 9, so as to be
blown out from the outlet 53.
[0076] In this case, the air (E3) blown out from the outlet 53
passes through the multiple air permeable sections 71 in the air
permeable member 70, which has a relatively narrower opening area
than the path TS3 of the second bent path section 54C or the outlet
53, so that the flow of the air (E3) is suppressed, whereby the air
(E3) is blown out in a pressure-increased state.
[0077] Accordingly, the air (E3) is ejected from the outlet 53 of
the blower duct 51A in a state where the flow speed thereof is
substantially uniform in the longitudinal direction B and the
lateral direction C of the rectangular opening shape of the outlet
53. Furthermore, even in a case where the amount of air taken in
through the inlet 52 is particularly increased in the blower duct
51A, the air (E3) is ejected from the outlet 53 in a state where
the flow speed thereof is substantially uniform in the longitudinal
direction B of the outlet 53 and in a state where unevenness in the
flow speed is reduced in the lateral direction C of the outlet 53.
The above-described case where the amount of air taken in is
increased is, for example, when a flow rate of 0.27 m.sup.3/minute
is increased to a flow rate of 0.33 m.sup.3/minute.
[0078] Then, as shown in FIG. 9, the air (E3) ejected from the
outlet 53 of the blower duct 51A in the blower device 5 is blown
into the shield case 40 via the air inlet opening 43 in the shield
case 40 of the charging device 4 and is subsequently blown onto the
corona discharge wires 41A and 41B, which are located within spaces
(see S1 and S2 in FIG. 4) partitioned from each other by the
partition 40d in an internal space S of the shield case 40, and the
grid electrode 42 located at the lower opening of the shield case
40.
[0079] With regard to the air blown onto the corona discharge wires
41A and 41B and the grid electrode 42, since the air (E3) is
ejected at a substantially uniform flow speed in the longitudinal
direction B and the lateral direction C of the opening shape of the
outlet 53 of the blower duct 51A, as described above, the air is
blown onto the corona discharge wires 41A and 41B and the grid
electrode 42 in a substantially uniform state in the longitudinal
direction B thereof, and is also blown onto the two corona
discharge wires 41A and 41B in a substantially uniform state.
[0080] Accordingly, waste, such as paper particles, external
additives in the toner, and discharge products, which may adhere to
the two corona discharge wires 41A and 41B and the grid electrode
42 in the charging device 4, may be kept distant therefrom by
blowing air uniformly thereto.
[0081] As a result, in the charging device 4, the occurrence of a
degradation phenomenon, such as uneven discharge performance
(electrostatic charging performance) caused by sparse adhesion of
waste onto the corona discharge wires 41A and 41B and the grid
electrode 42, may be prevented, so that the peripheral surface of
the photoconductor drum 21 may be electrostatically charged more
uniformly (along the rotation axis thereof).
First Test
[0082] FIG. 10 illustrates a result of a first test performed for
studying the performance characteristics of the blower device 5
(i.e., flow speed distribution in the lateral direction of air
ejected from the blower duct 51A).
[0083] In the first test, the flow speed of air blown out from the
outlet 53 of the blower duct 51A is measured based on simulation
under the following conditions when a relatively large average
amount of air, namely, about 0.33 m.sup.3/minute, is introduced by
the blower 50 through the inlet 52 of the blower duct 51A having
the configuration below.
[0084] As shown in FIGS. 5 and 9, the flow speed is measured at
three measurement positions in the longitudinal direction B of the
outlet 53, namely, an inner position (i.e., an end position closer
toward the inlet 52), a substantially central position, and an
outer position (i.e., an end position farther away from the inlet
52). At each measurement position, the state of flow speed in the
internal space S of the shield case 40 of the charging device 4
from an upstream end position (i.e., the inner wall surface of the
side plate 40b) to a downstream end position (i.e., the inner wall
surface of the side plate 40c) in the rotational direction A of the
photoconductor drum 21 is studied.
[0085] The blower duct 51A used has the path section 54 having the
overall shape shown in FIGS. 3 to 6. The inlet 52 has a
substantially square opening shape of 23 mm by 22 mm (i.e., a
rectangular shape that is slightly longer in the vertical
direction). The outlet 53 has a narrow rectangular opening shape of
350 mm in the longitudinal direction B by 17.5 mm in the lateral
direction C. The path TS2 of the first bent path section 54B has a
rectangular cross-sectional shape with a width W of 354 mm and a
height H of 8 mm. The total capacity of the paths TS1 to TS3 in the
blower duct 51A is about 170 cm.sup.3.
[0086] The first suppressing section 61 in the blower duct 51A is
provided such that the inner wall surface 65a at the upstream side
of the blocking portion 65 is located in an area where the
displacement amount N from the end 52a of the inlet 52 in the path
TS2 of the entrance path section 54A is 6 mm (FIG. 4).
[0087] The blocking portion 65 of the first suppressing section 61
has a thickness (i.e., the path length M of the openings 66) of 8
mm.
[0088] The three openings 66A to 66C in the first suppressing
section 61 each have a rectangular opening shape with a length (La,
Lb, Lc) of 120 mm and a height (Ka, Kb, Kc) of 2 mm. With reference
to the overall height H (8 mm) of the path TS2, the first opening
66A is disposed at the first height position h1 of 6.7 mm, the
second opening 66B is disposed at the second height position h2 of
4 mm, and the third opening 66C is disposed at the third height
position h3 of 1 mm. In particular, the third opening 66C is
disposed such that the lower plane thereof is aligned with the base
surface 54d. Moreover, the first opening 66A and the third opening
66C are disposed to have a positional relationship such that the
overlapping amount J1 of the adjoining ends thereof is 3 mm. The
second opening 66B and the third opening 66C are disposed to have a
positional relationship such that the overlapping amount J2 of the
adjoining ends thereof is 3 mm.
[0089] Furthermore, with regard to the second suppressing section
62 in the blower duct 51A, the porous air permeable member 70
provided with the air permeable sections (holes) 71 with a hole
diameter of 1 mm and a length of 3 mm and at a density of 0.42
holes/mm.sup.2 (.apprxeq.42 holes/cm.sup.2) is used.
[0090] It is clear from the result shown in FIG. 10 that the flow
speed in the lateral direction C of the outlet 53 of the blower
duct 51A is substantially identical at three positions in the
longitudinal direction B (i.e., the aforementioned three
measurement positions) of the outlet 53 and that unevenness in flow
speed in the lateral direction C may be reduced even when the
amount of air taken in through the inlet 52 is increased. The value
of "0 mm" on the abscissa axis in FIG. 10 substantially corresponds
to the position of the inner wall surface of the side plate 40b
located at the upstream side of the shield case 40 in the
rotational direction A of the photoconductor drum 21.
[0091] For a comparison, the first test described above is
similarly performed by using a blower duct 510 provided with a
first suppressing section 610 shown in FIG. 17 (comparative
example).
[0092] The blower duct 510 of the comparative example is configured
by providing the following first suppressing section 610 in place
of the first suppressing section 61 in the above-described blower
duct 51A according to the exemplary embodiment.
[0093] As shown in FIGS. 17 and 18, the first suppressing section
610 of the comparative example is configured by disposing a
blocking member, which forms a blocking portion 650 within the path
TS2 of the first bent path section 54B, in a traversing manner such
that the blocking member is spaced apart from the base surface 54d
in the cross-sectional shape of the path TS2 by a predetermined gap
(opening) 660. The opening 660 is a gap having a rectangular
opening shape with a length equal to the width W (=345 mm) of the
path TS2 and a height Kn of 1.5 mm. The opening 660 has a path
length M equal to the path length M of the openings 66 in the
exemplary embodiment.
[0094] FIG. 19 illustrates a result of the first test performed
using the blower duct 510 of this comparative example. It is clear
from the result of this first test that the flow speed in the
lateral direction C of the outlet 53 of the blower duct 510 varies
greatly at three positions in the longitudinal direction B (i.e.,
the aforementioned three measurement positions) of the outlet 53
and that unevenness in flow speed in the lateral direction C is
prominent when the amount of air taken in through the inlet 52 is
increased.
[0095] In contrast, in the blower device 5 equipped with the blower
duct 51A according to the exemplary embodiment, a good result with
reduced unevenness in flow speed in the lateral direction C of the
outlet 53 may be obtained, as shown in FIG. 10.
Second Test
[0096] FIG. 11 illustrates a result of a second test performed for
studying other performance characteristics of the blower device 5
(i.e., flow speed distribution, in the longitudinal direction, of
air ejected from the blower duct 51A).
[0097] In the second test, blower ducts each prepared as the blower
duct 51A have set therein different values shown in FIG. 11 for the
overlapping amounts (J1 and J2) of the three openings 66A to 66C in
the first suppressing section 61, and the flow speed of air ejected
from the outlet 53 of each blower duct is measured based on
simulation under the following conditions.
[0098] The flow speed is measured by studying the state of flow
speed in the entire region in the longitudinal direction B of the
outlet 53 of each blower duct. The measurement position is the
substantially central position in the lateral direction C of the
outlet 53. An average amount of air taken in through the inlet 52
is set to the same value as in the first test. The 0-mm position on
the abscissa axis in FIG. 11 is a position (i.e., an inner
position) close to the inlet 52.
[0099] It is clear from the result shown in FIG. 11 that, in the
case where the three openings 66A to 66C have positional
relationships such that the ends of adjoining openings partially
overlap each other (i.e., in the case where the overlapping amount
is +1 mm or +2 mm), unevenness in flow speed in the longitudinal
direction B of the outlet 53 in each blower duct 51A may be reduced
in the entire region in the longitudinal direction B. Furthermore,
because a result obtained when the overlapping amount is .+-.0 mm
is substantially the same as the result obtained when the
overlapping amount is +1 mm, the result corresponding to the
overlapping amount of .+-.0 mm substantially matches the result
corresponding to the overlapping amount of +1 mm in FIG. 11, and it
is difficult to distinguish them from each other. Therefore, in a
case where the three openings 66A to 66C have positional
relationships such that the ends of adjoining openings are aligned
with each other (i.e., in a case where the overlapping amount is 0
mm), a good result substantially the same as the case where the
overlapping amount is +1 mm is obtained.
[0100] On the other hand, in a case where the three openings 66A to
66C have positional relationships such that the ends of adjoining
openings are disposed away from each other (i.e., in a case where
the overlapping amount is -1 mm or -2 mm), it is clear that
unevenness occurs that causes the flow speed to relatively decrease
in the overlapping areas (i.e., two areas) in the longitudinal
direction B.
Third Test
[0101] FIGS. 12A to 12C illustrate a result of a third test
performed for studying the performance characteristics of the
blower device 5 (i.e., the direction of air when ejected from the
outlet 53 of the blower duct 51A).
[0102] The third test is a simulation-based study of the flowing
state of air passing through the openings 66A to 66C of the first
suppressing section 61 in the blower duct 51A and ejected from the
outlet 53 where the second suppressing section 62 is provided, when
the first test is performed using the blower duct 51A according to
the exemplary embodiment employed in the first test. FIGS. 12A to
12C schematically illustrate the contour of the path TS, the outlet
53, and the two suppressing sections 61 and 62 in the blower duct
51A. Furthermore, of information about the air flowing state
obtained based on simulation, each of FIGS. 12A to 12C only
illustrates the air flowing state indicating the characteristic
features.
[0103] It is clear from the result shown in FIGS. 12A to 12C that
the air (E3a, E3b, and E3c) passing through the openings 66A to 66C
of the first suppressing section 61 is ejected from the outlet 53
in a substantially uniform state in a direction substantially
orthogonal to the opening plane of the outlet 53.
[0104] In contrast, FIGS. 20A to 20C illustrate a result obtained
when the state of air passing through the opening 660 of the first
suppressing section 610 and ejected from the outlet 53 is simulated
as a third test by using the blower duct 510 of the comparative
example described above in the first test.
[0105] It is clear from the result shown in FIGS. 20A to 20C that,
with regard to the air (E31, E32, and E33) passing through the
single opening 660 of the first suppressing section 610 and ejected
from the outlet 53, especially the air (E31 and E33) ejected from
the inner side and the outer side in the longitudinal direction B
of the outlet 53 is ejected in a slightly inclined direction
instead of the direction orthogonal to the opening plane of the
outlet 53. It is assumed that this phenomenon occurs due to the
flow speed of the air (E21 and E23) flowing out via the inner and
outer positions of the opening 660 being lower than or higher than
that of the air (E22) flowing out via the central position of the
opening 660. It is conceived that this phenomenon is one of the
factors causing unevenness in flow speed in the lateral direction C
(particularly, between the end regions, in the lateral direction C,
where the corona discharge wires 41A and 41B are disposed)
indicated in the result of the comparative example (FIG. 19) in the
first test.
[0106] In the case of the blower duct 51A according to the
exemplary embodiment, as shown in FIG. 12A, the air (E2a) passing
through the first opening 66A flows out to an upper position in the
height direction of the path TS3 of the second bent path section
54C, moves along the upper inner wall surface thereof, and then
flows downward in a bent manner toward the outlet 53. A portion
(E4a) of the air (E2a) is not ejected from the outlet 53 (i.e., the
second suppressing section 62) but flows upward in a circulating
manner within the path TS3.
[0107] The flow speed of air that is to pass through the end region
close to the inlet 52 in the longitudinal direction D of the first
suppressing section 61 becomes the lowest due to the effect of, for
example, separation of air occurring in the bent area of the path
TS, and the speed of the air when being ejected from the outlet 53
tends to relatively decrease in an outer passing region (i.e., the
end region at the corona discharge wire 41B side) in the lateral
direction C, particularly, in the bending direction, of the second
bent path section 54C (for example, see the result of the inner
position in FIG. 19).
[0108] In the case where the first opening 66A located closest to
the inlet 52 is disposed at the first height position h1 that is
higher than those of the other openings 66B and 66C in the first
suppressing section 61, as in the first exemplary embodiment, a
portion (E2a) of the air passing through the first opening 66A
flows directly toward the outlet 53, as shown in FIG. 12A. As a
result, the speed of air when being ejected from the outlet 53
increases especially in the outer passing region in the lateral
direction C, so that it is assumed that the speeds in both end
regions, in the lateral direction C, where the corona discharge
wires 41A and 41B are disposed are corrected to substantially
similar speeds (see the result of the inner position in FIG.
10).
[0109] Furthermore, in the case of the blower duct 51A according to
the exemplary embodiment, as shown in FIG. 12C, the air (E2b)
passing through the second opening 66B flows out to the
substantially central position in the height direction of the path
TS3 of the second bent path section 54C and flows to impinge
against the inner wall surface of the path TS3. Moreover, by
impinging against the inner wall surface, the air (E2b) becomes air
(E4b) that flows separately in a circulating manner through an
upper portion and a lower portion of the path TS3.
[0110] The flow speed of air that is to pass through the end region
farthest from the inlet 52 in the longitudinal direction D of the
first suppressing section 61 becomes the highest since an air flow
is also generated after the air impinges against the inner wall
surface opposite from the inlet 52 in the entrance path section 54A
without being affected by, for example, separation of air occurring
in the bent area of the path TS, and the speed of the air when
being ejected from the outlet 53 tends to decrease in an inner
passing region (i.e., the end region at the corona discharge wire
41A side) in the lateral direction C, particularly, in the bending
direction, of the second bent path section 54C and relatively
increase in the outer passing region in the bending direction (for
example, see the result of the outer position in FIG. 19).
[0111] Because the second opening 66B located farthest from the
inlet 52 in the first suppressing section 61 is disposed at the
intermediate height position h2, which is relatively the second
highest position, in the first exemplary embodiment, the air (E2b)
passing through the second opening 66B impinges against the inner
wall surface facing the third path TS3, as shown in FIG. 12C, so as
to separate into two upper and lower circulating air flows (E4b).
As a result, the speed of air in the lateral direction C when being
ejected from the outlet 53 is increased in the inner passing region
but is reduced in the outer passing region, so that it is assumed
that the speeds in both end regions, in the lateral direction C,
where the corona discharge wires 41A and 41B are disposed are
adjusted to substantially similar speeds that are balanced as a
whole.
[0112] Furthermore, in the case of the blower duct 51A according to
the exemplary embodiment, as shown in FIG. 12B, the air (E2c)
passing through the third opening 66C flows out to the lower
position in the height direction of the path TS3 of the second bent
path section 54C and flows to traverse the outlet 53 (i.e., the
second suppressing section 62). Moreover, a portion (E4c) of the
air (E2c) passes by the outlet 53 (i.e., the second suppressing
section 62) and subsequently rises within the path TS3 so as to
flow in a circulating manner therein.
[0113] The flow speed of air that is to pass through the central
region in the longitudinal direction D of the first suppressing
section 61 is much the same in both end regions, in the lateral
direction C, where the corona discharge wires 41A and 41B are
disposed, as compared with the speed of air that is to pass through
the position closest to the inlet 52 and the speed of air that is
to pass through the position farthest from the inlet 52 (for
example, see the result of the central position in FIG. 19).
[0114] By disposing the third opening 66C, located at the central
position in the longitudinal direction D of the first suppressing
section 61, at relatively the lowest position h3, as in the first
exemplary embodiment, the air (E2c) passing through the third
opening 66C flows straight through the aforementioned inner passing
region in the lateral direction C without traveling through the
outlet 53 (i.e., the air permeable sections 71 of the second
suppressing section 62 in actuality). However, in the inner passing
region in the lateral direction C, the air (E4c) turning upward by
impinging against the inner wall surface facing the path TS3, as
shown in FIG. 12B, presses the air (E2c) from above. As a result,
it is assumed that the speed of air in the lateral direction C when
being ejected from the outlet 53 is maintained at further similar
speeds in both end regions, in the lateral direction C, where the
corona discharge wires 41A and 41B are disposed.
[0115] In the blower duct 51A according to the exemplary
embodiment, the air immediately after passing through the openings
66A to 66C located at different positions in the longitudinal
direction D of the first suppressing section 61 vary in flowing
speeds. However, in the blower duct 51A according to the exemplary
embodiment, the heights h of the openings 66A to 66C are set to
have predetermined height relationships so that the air flowing
into the path TS3 by passing through the openings 66A to 66C is
varied in flows, whereby the flow speed of air in the lateral
direction C after ultimately passing through the outlet 53
(particularly, the end regions, in the lateral direction C, where
the corona discharge wires 41A and 41B are disposed) may be
improved to a uniform state with reduced unevenness.
Other Exemplary Embodiments
[0116] In the first exemplary embodiment, the three openings 66A to
66C are provided as the first suppressing section 61 of the blower
duct 51A. Alternatively, for example, a first suppressing section
61B or 61C having the configuration shown in FIG. 13 or 14 may be
employed as the first suppressing section 61.
[0117] The first suppressing section 61B shown in FIG. 13 includes
a blocking portion 65B and two openings 66D and 66E. The blocking
portion 65B is a region excluding the two openings 66D and 66E in a
cross-sectional region in the longitudinal direction D of the path
TS2 of the first bent path section 54B.
[0118] The two openings 66D and 66E include a first opening 66D
disposed at a position closest to the inlet 52 in the longitudinal
direction D of the path TS2 of the first bent path section 54B and
a second opening 66E disposed farthest from the inlet 52. The first
opening 66D has a rectangular opening shape that is long in the
longitudinal direction D and has a length Ld and a height Kd. The
second opening 66E has a rectangular opening shape that is long in
the longitudinal direction D and has a length Le and a height Ke.
The openings 66D and 66E may both have a path length M that is
equal to the path length of each opening 66 in the first exemplary
embodiment. Furthermore, the openings 66D and 66E may have
identical lengths Ld and Le and identical heights Kd and Ke, or may
have different lengths Ld and Le and different heights Kd and Ke.
Moreover, the lengths Ld and Le and the heights Kd and Ke are set
to be larger than the lengths La, Lb, and Lc and the heights Ka,
Kb, and Kc of the three openings 66A to 66C in the first exemplary
embodiment.
[0119] Furthermore, the first opening 66D is disposed at a first
height position h4, which is where the height from the reference
base surface 54d of the path TS2 is the largest. The second opening
66E is disposed at a second height position h5 (<h4), which is
where the height from the reference base surface 54d is the second
largest.
[0120] Moreover, the first opening 66D and the second opening 66E
are disposed at different positions in the longitudinal direction
D. In addition, the first opening 66D and the second opening 66E
are disposed to have a positional relationship such that an end
66Da and an end 66Ea, which adjoin each other, overlap each other
by a predetermined overlapping amount J3. This overlapping amount
J3 is set to be larger than the overlapping amounts J1 and J2 of
the three openings 66A to 66C in the first exemplary
embodiment.
[0121] The first suppressing section 61C shown in FIG. 14 includes
a blocking portion 65C and four openings 66F, 66G, 66H, and 66I.
The blocking portion 65C is a region excluding the four openings
66F, 66G, 66H, and 66I in a cross-sectional region in the
longitudinal direction D of the path TS2 of the first bent path
section 54B.
[0122] The four openings 66 (66F to 66I) include a first opening
66F disposed closest to the inlet 52 in the longitudinal direction
D of the path TS2 of the first bent path section 54B, a second
opening 66G disposed farthest from the inlet 52, and remaining
third and fourth openings 66H and 66I disposed at least between the
first opening 66F and the second opening 66G.
[0123] The first opening 66F has a rectangular opening shape that
is long in the longitudinal direction D and has a length Lf and a
height Kf. The second opening 66G has a rectangular opening shape
that is long in the longitudinal direction D and has a length Lg
and a height Kg. The remaining third opening 66H has a rectangular
opening shape that is long in the longitudinal direction D and has
a length Lh and a height Kh. The other remaining fourth opening 66I
has a rectangular opening shape that is long in the longitudinal
direction D and has a length Li and a height Ki. The four openings
66F, 66G, 66H, and 66I may have identical lengths Lf, Lg, Lh, and
Li and identical heights Kf, Kg, Kh, and Ki, or may have different
lengths Lf, Lg, Lh, and Li and different heights Kf, Kg, Kh, and
Ki. The lengths Lf, Lg, Lh, and Li and the heights Kf, Kg, Kh, and
Ki are set to be smaller than the lengths La, Lb, and Lc and the
heights Ka, Kb, and Kc of the three openings 66A to 66C in the
first exemplary embodiment.
[0124] Furthermore, the first opening 66F is disposed at a first
height position h6, which is where the height from the reference
base surface 54d of the path TS2 is the largest. The second opening
66G is disposed at a second height position h7 (<h6), which is
where the height from the reference base surface 54d is the second
largest. The remaining third opening 66H is disposed at a third
height position h8 (<h7), which is lower than the second height
position h7 and is where the height from the reference base surface
54d is the third largest. The remaining fourth opening 66I is
disposed at a fourth height position h9 (<h8), which is lower
than the third height position h8 and is where the height from the
reference base surface 54d is the fourth largest (i.e., the
smallest).
[0125] Specifically, the remaining third and fourth openings 66H
and 66I are disposed at respective height positions (h8>h9),
which are lower than the second height position h7, such that the
remaining opening disposed closer toward the inlet 52 in the
longitudinal direction D of the cross-sectional shape of the path
TS2 decreases in height H from the base surface 54d in a stepwise
manner. This height-position relationship similarly applies to a
case where there are three or more remaining openings.
[0126] Furthermore, the first opening 66F, the second opening 66G,
and the remaining third openings 66H and 66I are disposed at
different positions in the longitudinal direction D. In addition,
the openings 66F, 66G, 66H, and 66I are disposed to have positional
relationships such that adjoining ends thereof overlap each other
by predetermined overlapping amounts J4, J5, and J6. The
overlapping amounts J4, J5, and J6 are equal to or larger than the
overlapping amounts J1 and J2 of the three openings 66A to 66C in
the first exemplary embodiment.
[0127] The blower duct 51A in the first exemplary embodiment is
provided with the path section 54 having the entrance path section
54A, the first bent path section 54B, and the second bent path
section 54C. Alternatively, for example, a blower duct 51B provided
with the entrance path section 54A and the first bent path section
54B, as shown in FIGS. 15 and 16, may be employed as the blower
duct.
[0128] As compared with the blower duct 51A according to the first
exemplary embodiment, the blower duct 51B shown in FIGS. 15 and 16
does not have the second bent path section 54C that is bent in one
direction (i.e., the downward direction) from the terminal end of
the first bent path section 54B. Instead, the blower duct 51B has a
new first bent path section 54D with a path TS4 that extends
linearly after being bent in a manner similar to the second bent
path section 54C in the first exemplary embodiment from an
intermediate position of the entrance path section 54A and that has
the outlet 53 located at the terminal end (surface). In this blower
duct 51B, the outlet 53 located at the terminal end of the first
bent path section 54D is provided with a second suppressing section
62 having a configuration similar to that in the first exemplary
embodiment.
[0129] As the first suppressing section 61, this blower duct 51B is
provided with a suppressing section including the blocking portion
65 and the three openings 66A to 66C, similar to the first
suppressing section 61 in the first exemplary embodiment (see, for
example, FIGS. 4, 7, and 8).
[0130] In this case, a reference base surface in the path TS4 of
the first bent path section 54C serving as the reference for
setting the height positions h (h1 to h3) of the three openings 66A
to 66C may be the relatively wider one of opposing inner wall
surfaces 54f and 54g among the inner wall surfaces constituting the
path TS4. With regard to this reference base surface, for example,
in a case where the blower duct 51B is used with the outlet 53
facing downward, as shown in FIG. 16, the inner wall surface 54f
located at the upstream side in the rotational direction A of the
photoconductor drum 21 electrostatically charged by the charging
device 4 disposed below the blower duct 51B may serve as the
"reference base surface".
[0131] Furthermore, in this blower duct 51B, the first suppressing
section 61B (FIG. 13) or the first suppressing section 61C (FIG.
14) having the alternative configuration described above may be
employed as the first suppressing section 61.
[0132] In the first exemplary embodiment, two suppressing sections,
namely, the first suppressing section 61 and the second suppressing
section 62, are provided for suppressing the flow of air in the
blower duct. Alternatively, three or more suppressing sections may
be provided. In this case, the blower duct is provided with the
path section 54 having the path TS that is bent two or more times,
and has an additional suppressing section disposed between the
first suppressing section 61 and the second suppressing section 62.
Furthermore, the suppressing sections, including the first
suppressing section 61, may each be provided in an area where the
cross-sectional shape changes in the path TS of the path section 54
of the blower duct or an area after (e.g., immediately after) the
air flowing direction changes in the path TS.
[0133] Furthermore, the second suppressing section 62 provided at
the outlet 53 of the blower duct 51A or 51B used in the blower
device 5 is not limited to the configuration that uses the air
permeable member 70 having the multiple air permeable sections
(holes) 71 described in the first exemplary embodiment. For
example, the second suppressing section 62 may use an alternative
air permeable member 70 typified by a porous member (i.e., a member
having multiple air permeable sections 71 with irregular shapes
extending therethrough), such as a nonwoven fabric applied to, for
example, a filter.
[0134] Furthermore, the charging device 4 to which the blower
device 5 is applied may be a charging device of a type that does
not have the grid electrode 42 installed therein, namely, a
so-called corotron-type charging device. Moreover, the charging
device 4 to which the blower device 5 (including the blower duct)
is applied may be of a type that uses a single corona discharge
wire 41 or three or more corona discharge wires 41. The corona
discharger to which the blower device 5 is applied may be a corona
discharger that removes electricity from the photoconductor drum 21
or a corona discharger that electrostatically charges or removes
electricity from a rotating charge body other than the
photoconductor drum 21. A discharge-target rotating member that
experiences corona discharge by the corona discharger is not
limited to a drum-type member and may be a belt-type member.
Furthermore, the discharge-target rotating member used when corona
discharge is performed by the corona discharger is not limited to a
member whose portion that passes through a discharge opening has a
curved surface with fixed curvature, but may be a member having a
flat surface.
[0135] With regard to the image forming apparatus 1, the
configuration thereof for, for example, image formation is not
particularly limited so long as it is equipped with a long target
structure to which the blower device 5 is applied (i.e., to which
air is blown by the blower device 5). For example, although the
image forming apparatus 1 uses a single image forming unit 20 to
form a monochromatic image in the first exemplary embodiment, the
image forming apparatus 1 may alternatively be of a type that forms
a multicolor image by using multiple image forming units 20 that
form images of different colors.
[0136] The foregoing description of the exemplary embodiments of
the present invention has been provided for the purposes of
illustration and description. It is not intended to be exhaustive
or to limit the invention to the precise forms disclosed.
Obviously, many modifications and variations will be apparent to
practitioners skilled in the art. The embodiments were chosen and
described in order to best explain the principles of the invention
and its practical applications, thereby enabling others skilled in
the art to understand the invention for various embodiments and
with the various modifications as are suited to the particular use
contemplated. It is intended that the scope of the invention be
defined by the following claims and their equivalents.
* * * * *